Metal sheeting
Metal sheeting
(OP)
I have a situation where I have very large windloads on metal sheeting. For the IBR sheeting I have always used the manufacturers tables of purlin spacing previously. However, they have a limit on the windloads and my loads in this case are far in excess of those limits. Has anyone worked out metal sheet spanning capabilities from scratch. I guess that the limiting factor is local buckling of the thin sheet. Any ideas on how to figure out the limiting stress in a profiled thin sheet?






RE: Metal sheeting
RE: Metal sheeting
RE: Metal sheeting
RE: Metal sheeting
Contact the manufacturer; they may be able to advise closer purlin spacings or do a special run with thicker sheet.
RE: Metal sheeting
RE: Metal sheeting
Not column buckling, but local buckling. There are many local buckling failure modes in thin profiled sheets.
RE: Metal sheeting
BA
RE: Metal sheeting
RE: Metal sheeting
Remember the fasteners. They are often the controlling case for suction pressure.
RE: Metal sheeting
RE: Metal sheeting
BA
RE: Metal sheeting
So L2 = (L1*w/W)0.5
BA
RE: Metal sheeting
Can you post a description of the sheeting material? Or a link to a site where it is shown? I could post a link to an Australian manufacturer if that would help.
RE: Metal sheeting
L2 = L1(*w/W)0.5
where w is load in tables with allowable span of L1
L2 is the allowable span with load increased to W
BA
RE: Metal sheeting
I figured out the typo in the equation. That is the method I am using. Hokie, I found useful stuff on the Lysaght website but unfortunately they don't do the same IBR profile that we have here.
RE: Metal sheeting
RE: Metal sheeting
Mike McCann
MMC Engineering
RE: Metal sheeting
Msquared - don't understand the question. The table gives purlin spacing to support the sheet for a lower wind load than I have and so I can make it work by reducing the purlin spacing and that is what I am looking for and currently using BAretired's suggestion which gives me my best estimate so far.
RE: Metal sheeting
this could be a whole new thread... but, you might want to look at the theory, if there is a large divergence... <G>
Dik
RE: Metal sheeting
Phuduhudu didn't understand your question because he is not using the roof cladding as a diaphragm. It is just roofing, takes only load normal to the surface.
RE: Metal sheeting
Mike McCann
MMC Engineering